Summary

• A vulnerability in the CLI of Cisco NX-OS Software could allow an authenticated user in possession of Administrator credentials to execute arbitrary commands as root on the underlying operating system of an affected device.

  This vulnerability is due to insufficient validation of arguments that are passed to specific configuration CLI commands. An attacker could exploit this vulnerability by including crafted input as the argument of an affected configuration CLI command. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system with the privileges of root.

  Note: To successfully exploit this vulnerability on a Cisco NX-OS device, an attacker must have Administrator credentials. The following Cisco devices already allow administrative users to access the underlying operating system through the bash-shell feature, so, for these devices, this vulnerability does not grant any additional privileges:

  • Nexus 3000 Series Switches
  • Nexus 7000 Series Switches that are running Cisco NX-OS Software releases 8.1(1) and later
  • Nexus 9000 Series Switches in standalone NX-OS mode

  Cisco has released software updates for certain Cisco NX-OS hardware platforms and will continue to release fixes as they become available. There are no workarounds that address this vulnerability.

  This advisory is available at the following link:
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-cmd-injection-xD9OhyOP

Affected Products

• Vulnerable Products

  At the time of publication, this vulnerability affected the following Cisco products if they were running a vulnerable release of Cisco NX-OS Software:

  • MDS 9000 Series Multilayer Switches (CSCwj97007)
  • Nexus 3000 Series Switches (CSCwj97009)¹
  • Nexus 5500 Platform Switches (CSCwj97011)
  • Nexus 5600 Platform Switches (CSCwj97011)
  • Nexus 6000 Series Switches (CSCwj97011)
  • Nexus 7000 Series Switches (CSCwj94682)²
  • Nexus 9000 Series Switches in standalone NX-OS mode (CSCwj97009)¹

  1. For Cisco NX-OS Software releases that are running on Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches in standalone NX-OS mode, this vulnerability does not grant additional privileges due to the availability of the bash-shell feature. Cisco NX-OS Software releases 9.3(5) and later are not affected by this vulnerability, with the exception of the following Cisco platforms:

  • Nexus 3000 platforms:
  • N3K-C3264C-E
  • N3K-C3172PQ-10GE
  • N3K-C3172PQ-10GE-XL
  • N3K-C3172TQ-10GT
  • N3K-C3548P-10GX
  • Nexus 9000 platforms:
  • N9K-C92348GC-X (fixed in Cisco NX-OS Software releases 10.4(3) and later)

  2. For Cisco NX-OS Software releases 8.1(1) and later that are running on Cisco Nexus 7000 Series Switches, this vulnerability does not grant additional privileges due to the availability of the bash-shell feature.

  For more information about this vulnerability, see the Details section of this advisory.

  For more information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory.

  Products Confirmed Not Vulnerable

  Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.

  Cisco has confirmed that this vulnerability does not affect the following Cisco products:

  • Adaptive Security Appliance (ASA) Software
  • Firepower 1000 Series
  • Firepower 2100 Series
  • Firepower 4100 Series
  • Firepower 9300 Security Appliances
  • Firepower Threat Defense (FTD) Software
  • Nexus 1000 Virtual Edge for VMware vSphere
  • Nexus 1000V Switch for VMware vSphere
  • Nexus 9000 Series Fabric Switches in ACI mode
  • Secure Firewall 3100 Series
  • Secure Firewall 4200 Series
  • Secure Firewall Management Center (FMC) Software
  • UCS 6200 Series Fabric Interconnects
  • UCS 6300 Series Fabric Interconnects
  • UCS 6400 Series Fabric Interconnects
  • UCS 6500 Series Fabric Interconnects

Details

• To exploit this vulnerability, an attacker must have Administrator privileges and have access to specific configuration commands.

  If a device is running a Cisco NX-OS Software release that does not support the bash-shell feature, a user with Administrator privileges could exploit this vulnerability to execute arbitrary commands on the underlying operating system.

  If a device is running a Cisco NX-OS Software release that supports the bash-shell feature, a user with Administrator privileges can already access the underlying operating system directly using the bash-shell feature. Therefore, this vulnerability does not grant any additional privileges on the device. However, this vulnerability does allow a user with Administrator privileges to execute commands on the underlying operating system without enabling the bash-shell feature and without triggering system syslog messages showing that the user executed the run bash CLI command. This could help a user with Administrator privileges hide the execution of shell commands on the device. However, because the affected CLI commands are configuration commands, the initial step for exploitation of this vulnerability would result in a syslog message reporting that a configuration change was applied to the device.

  The bash-shell feature is available on all supported Cisco NX-OS Software releases for the following Cisco devices:

  • Nexus 3000 Series Switches
  • Nexus 7000 Series Switches that are running Cisco NX-OS Software releases 8.1(1) and later
  • Nexus 9000 Series Switches in standalone NX-OS mode

  As a standard network practice, the credentials for the administrative users network-admin and vdc-admin should be monitored and changed frequently. The devices should also be monitored for any unexpected configuration changes.

Workarounds

• There are no workarounds that address this vulnerability.

Fixed Software

• When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories page, to determine exposure and a complete upgrade solution.

  In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.

  Cisco NX-OS Software

  To help customers determine their exposure to vulnerabilities in Cisco NX-OS Software, Cisco provides the Cisco Software Checker. This tool identifies any Cisco security advisories that impact a specific software release and the earliest release that fixes the vulnerabilities that are described in each advisory (“First Fixed”). If applicable, the tool also returns the earliest release that fixes all the vulnerabilities described in all the advisories that the Software Checker identifies (“Combined First Fixed”).

  To use the tool, go to the Cisco Software Checker page and follow the instructions. Alternatively, use the following form to search for vulnerabilities that affect a specific software release. To use the form, follow these steps:

  1. Choose which advisories the tool will search-only this advisory, only advisories with a Critical or High Security Impact Rating (SIR), or all advisories.
  2. Choose the appropriate software.
  3. Choose the appropriate platform.
  4. Enter a release number-for example, 7.0(3)I7(5) for Cisco Nexus 3000 Series Switches or 14.0(1h) for Cisco NX-OS Software in ACI mode.
  5. Click Check.

  
  
  

  Additional Resources

  For help determining the best Cisco NX-OS Software release for a Cisco Nexus Switch, see the following Recommended Releases documents. If a security advisory recommends a later release, Cisco recommends following the advisory guidance.

  Cisco MDS Series Switches
  Cisco Nexus 1000V for VMware Switch
  Cisco Nexus 3000 Series Switches
  Cisco Nexus 5500 Platform Switches
  Cisco Nexus 5600 Platform Switches
  Cisco Nexus 6000 Series Switches
  Cisco Nexus 7000 Series Switches
  Cisco Nexus 9000 Series Switches
  Cisco Nexus 9000 Series ACI-Mode Switches

  To determine the best release for Cisco UCS Software, see the Recommended Releases documents in the release notes for the device.

Exploitation and Public Announcements

• In April 2024, the Cisco Product Security Incident Response Team (PSIRT) became aware of attempted exploitation of this vulnerability in the wild.

Source

• Cisco would like to thank Sygnia for reporting this vulnerability. Tristan Van Egroo of the Cisco Advanced Security Initiatives Group (ASIG) investigated this vulnerability.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-cmd-injection-xD9OhyOP

Revision History

• Version	Description	Section	Status	Date
  1.2	Further clarified the condition under which exploitation can occur and added products that are not vulnerable.	Summary, Vulnerable Products, Products Confirmed Not Vulnerable, Details	Final	2024-JUL-03
  1.1	Updated to explain that fixes are available for some products and others will be released as they become available.	Summary	Final	2024-JUL-02
  1.0	Initial public release.	-	Final	2024-JUL-01

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